The correction of certain malocclusions is traditionally accomplished by means of wire structures anchored to the patient's teeth. The wire structures are known as arches or arch wires and the anchoring assembly generally has one or more lingual tubes attached to a molar band. Generally, two such lingual tube/molar band assemblies are attached to the patient's teeth to anchor the ends of an arch wire. Each teeth to become properly aligned. Integral to the arch wire are posts which are seated into the lingual tubes of the anchoring assembly thereby anchoring the arch wire in place.
Fabrication of the customized arch wire is accomplished by first constructing a stone model of the patient's dental structure using a negative impression of the dental structure as is well known in the art. Based on the model an arch wire or orthodontic appliance can be constructed to correct the malocclusions. While the model is adequate for defining certain characteristics of the orthodontic appliance it does not accurately represent the location of the lingual tubes. Consequently, certain characteristics of the orthodontic appliance, which depend upon the location of the lingual tubes, can only be estimated by the orthodontist or dental practitioner. This deficiency results in orthodontic appliances being fabricated which may require significant manipulation by the orthodontist or dental practitioner in order to fit the appliance to the patient's teeth. However, such manipulation may render the orthodontic appliance unsuitable and thereby require the fabrication of a new appliance.
For example, arch wires fabricated according to traditional techniques and which are anchored by horizontal lingual tubes, are typically in error by about twenty thousandths of an inch at each end. That is, the horizontal lingual tube is typically offset from its desired position relative to a patient's tooth by this amount. While this may appear to be an insignificant amount, the adjustments that would be required to make such an arch both fit and perform properly would generally render the arch useless for its intended purpose. Improved results can be obtained by using a single vertical lingual tube, but adjustments are still required. Consequently, there is a need for a method which produces highly precise orthodontic appliances without subsequent adjustments thereof.
The present invention is intended to eliminate the necessity of gross manipulations of orthodontic appliances constructed using stone models by precisely locating lingual tubes on the stone model. Consequently, only the most minor adjustments, if any, need to be made when fitting the appliance to the patient's teeth and the need to refabricate the appliance is thereby minimized.